This site is being addressed through Federal and potentially responsible parties' actions.

NPL LISTING HISTORY

Proposed Date:09/08/1983

Final Date:09/21/1984

Deleted Date:

Groundwater, surface water, and soil contain pentachlorophenol (PCP), dioxins, furans, polycyclic aromatic hydrocarbons (PAHs), and heavy metals including copper, chromium, and arsenic. Potential health risks include drinking contaminated surface water or groundwater, or coming into direct contact with or accidentally ingesting contaminated soils. An alternative drinking water supply was provided to residents with the potential for contaminated domestic groundwater wells.

Initial Actions: An alternative water supply was provided by BEI to residents south of the site in areas of potential groundwater contamination since 1986. Between 1987 and 1988, the EPA directed the construction of a temporary chip seal cap over the contaminated soil in the process area. The cap functioned to stabilize the site and to prevent contact with contaminants after a fire spread hazardous substances. In 1994, the EPA directed BEI to build an on-site landfill for disposal of surface soils containing high levels of dioxins. The 15,000 cubic yard landfill Cell #1 was completed in 1995. Subsequent detailed investigations determined dioxin soil contamination was widespread preventing the planned soil remedies.

Entire Site: The potentially responsible party for site contamination completed a study of the site in 1989. The EPA used the results of this study to select the following methods to address site contamination: removing and treating contaminated groundwater with a carbon adsorption process; treating the contaminated soil in place; capping the wood treating area; providing a permanent water supply to those residents with contaminated wells; and discharging treated groundwater to the aquifer. Two groundwater extraction and treatment systems were installed: one on-site (400 gpm) and one off-site (600 gpm). Both use a carbon absorption process, with discharge to recharge injection wells. In 1989, the EPA selected three different treatment technologies to clean up approximately 335,000 cubic yards of contaminated soil. However, treatability tests conducted during the design phases showed that the selected technologies could not achieve cleanup goals for all contaminants. BEI initiated a focused feasibility study to evaluate other cleanup alternatives for soils in 1995. In August of 1996, a Record of Decision (ROD) Amendment #1 was issued changing the soil remedy to on-site landfilling of the remaining contaminated soils. ROD Amendment #1 changed the cleanup standard to industrial use and required deed restrictions to prohibit future residential development.

In December 1997 and January 2003, as required by the Consent Decree and the ROD, the EPA conducted 5 year remedy reviews. Both five year reviews concluded the remedy remains protective.

In September 23, 1999, the EPA issued a ROD Amendment #2 to modify the remedy to 1) provide for a Technical Impracticability Waiver due to Dense Non-Aqueous Liquid for 4 acres of the 200 acre site, 2) add enhanced in-situ bioremediation to the remedy, and 3) provide for Monitored Natural Attenuation (MNA) as a contingency remedy. A modification to the Consent Decree modification for ROD Amendments #1 and #2 was completed September 22, 2003. The land use covenant provision of the ROD restricting the site to industrial use and access and use of groundwater under the site were recorded with the Butte County Recorder on November 12, 2003.

Koppers Industries, Inc. closed the wood treating facility in March 15, 2001 and completed its Resource Conservation and Recovery Act (RCRA) closure under State of California oversight July 2002. Remediation of the area beneath the process area became accessible after the RCRA closure. Final soil remediation was completed in September 2002.

With soil remediation complete and groundwater contamination under control a Preliminary Closeout Report was issued September 4, 2003. To review this preliminary report double click on its title below under Site Documents and Report section. A Final Closure Report cannot be issued until groundwater aquifer has been restored to the cleanup levels of the ROD which will be years in the future.

Groundwater

To prevent exposure to contaminated groundwater from domestic wells, city water was provided in 1986 to residents with potential for exposure and is paid for by BEI. As the off-property remediation has progressed the need for the alternative water supply program has been reduced from the original thirty-four (34) recipients to seven (7). The remaining seven (7) water supply recipients will continue to receive payment for alternative water supply usage until ROD standards have been met for their drinking water wells.

The off-property treatment facility was taken off-line in December of 1995 as the plume degraded and no contaminants were being removed by the extraction wells. The treatment facility remains in reserve. The residual off-property plume is no longer being fed by contaminants on-property and has assumed a stationary position which is being monitored. In August 1998 a pilot in-situ bioremediation program to assist in PCP degradation was initiated and incorporated into the remedy September 1999. The program calls for the addition of nutrients (diammonium phosphate) and oxygen (magnesium peroxide) to three wells and monitoring at five wells. The PCP concentrations in the off-property wells are decreasing. The on-property treatment facility remains in operation and is containing contaminants on property. The on-property and off-property plumes are no longer connected.

In April 1998 a pilot in-situ bioremediation program was initiated to degrade PCP and incorporated into the remedy September 1999. The program calls for the addition of nutrients (diammonium phosphate) and oxygen (magnesium peroxide) to six wells and monitoring at five wells. The PCP concentrations in the off-property wells are decreasing.

March 8, 1999 BEI submitted a Final Evaluation of Technical Impracticability (TI) of Groundwater Restoration in the Former Creosote Pond and Cellon Blowdown Areas On-property. EPA issued a proposed plan for public comment in March 1999 and ROD Amendment #2 in September 1999 to 1) provide for a Technical Impracticability Waiver due to Dense Non-Aqueous Liquid for 4 acres of the site, 2) add Enhanced in-situ Bioremediation to the remedy, and 3) provide for Monitored Natural Attenuation as a Contingency remedy. TI zone is being monitored and enhanced in-situ bioremediation has been implemented for groundwater remediation.

With the demolition of the wood treating facility in 2001 and 2002, boron was mobilized from the DriCon/CCA area and detected by monitoring well MW-8 above the action level. The downgradient on-property treatment plant does not treat for boron. As an interim measure, MW-8 was converted to an extraction well to dilute the boron concentration to continue reinjection below the cleanup level. BEI prepare a Long-term Groundwater Remediation Work Plan which was approved by the EPA. Boron reading at MW-8 have been declining.

Soils

In 1987/88 a temporary chip seal cap was placed over the process area. In 1992, two concrete drip pads were installed in the process area to contain wood treating chemicals and prevent any further soil contamination. The cap and drip pads were demolished in 2002 as part of KII's facility closure. Two landfill cells were constructed for disposal of contaminated soils on site. Cell #1 (13,000 cubic yards) was completed in August 1995 as a Removal Action. Cell #2 (147,000 cubic yards capacity) was closed September 2002 with the completion of the soil remediation efforts for the site. 6,000 cubic yards of boron impacted soil was removed from the newly discovered Dri-Con/CCA source and placed in Cell #2 prior to its closure. With soil remediation complete and control of groundwater in place a Preliminary Closeout Report was issued for the site September 4, 2003. A land use covenant was recorded with the Butte County Recorder on November 12, 2003 restricting the site to industrial use and the access and use of groundwater under the site.

The public information repositories for the site are at the following locations:

Butte County Public Library,
1820 Mitchell Ave.,
Oroville, CA 95965

Meriam Library,
California State University at Chico,
Chico, CA 95929-0295

The most complete collection of documents is the official EPA site file, maintained at the following location: